Ms.Tremblay, you can apply for tourist visa for you and your two children, do your children have their own passport or they have a same passport with you? If they have separate passports, you also need to apply for China visa for them, for Canadian citizens, the required documents for L visa application are:
1) An original copy of passport with enough blank visa pages, valid for at least another 6 months.

(2) A fully completed copy of Visa Application Form signed by the actual applicant; all applications prepared by people other than the applicants (except those below 18 years of age) should be properly signed by the applicants themselves; for every application prepared by a travel agency, both the agency's seal and proper signature of the actual applicant should be visible.

(3) One recent 22(in.)-sized color passport photo, white in background, with a full front view of the applicant's head and shoulders but without any head cover.

(4)sometimes, the visa officer also requires the round-trip flight tickets or hotel reservation.